This invention has been created without the sponsorship or funding of any federally sponsored research or development program.
The present invention is directed to an anti-friction device with the use with material handling equipment, such as conveyors, work benches, work stations, carts, feed stations, or any equipment in which it is desirable to be able to use ball-type anti-friction elements to provide for change of direction of an object, moving along a conveyor or to provide a table on which an object can be moved and rotated to a desired orientation. A typical ball-type anti-friction device includes a housing which contains a relatively large ball that is supported on a plurality of smaller balls which enable the larger ball to rotate in any direction. The larger ball and smaller balls are mounted in a ball cage which is movably mounted within the housing for positioning the larger ball in either an inactive position in which the larger ball is below the upper surface of the housing and in an active position in which the larger ball extends above the upper surface of the housing. The movement of the ball cage is controlled by fluid drive means and biasing means.
An object of the present invention is the provision of a ball-type anti-friction device which has an improved actuating system for selectively positioning the larger ball in its lowered inactive position or in its raised active position.
The present invention consists of ball-type anti-friction device which has a housing, a ball cage mounted within the housing for movement relative to the housing between a lower inactive position and an upper active position. The ball cage contains a relatively large ball mounted on relatively small bearing balls so that when the ball cage is in the lower or inactive position, the large ball is below the top surface of the housing and when the ball cage is in the upper or active position, the ball extends above the top surface of the housing.
In a first embodiment of the invention, the housing contains a double acting fluid drive system. The fluid drive system includes two fluid chambers and a piston connected to the ball cage. The piston is selectively actuated by selective pressurization of the two fluid chambers.
In a second embodiment of the invention, the ball cage is actuated by a single acting fluid drive system. A piston is connected to the ball cage and is biased downwardly to normally maintain the ball cage and large ball in the lower or inactive position. The housing contains a single fluid chamber which, when pressure causes the ball cage and large ball to move to the active or upper position in opposition to the biasing means.